Feeding mechanism for sewing machine



Dec. 12, 1967 J. M. WASHBURN 3,357,384

FEEDING MECHANISM FOR SEWING MACHINE Filed Dec. 10, 1965 4 Sheets-Sheet 1 FIG. i

QL'UHH I, E X I 12 4 n O l3 5 i i I 55 INVENTOR JOHN M. WASHBURN ATTORNEYS,

Dec. 12, 1967 J. M4 WASHBURN 3,357,384

FEEDING MECHANISM FOR SEWING MACHINE Filed Dec. 10, 1965 4 Sheets-Sheet 2' FIG. 3

FIG.4

4 By 2 [H INVENTOR JOHN M. WASHBURN ATTORNEYS.

Dec. 12, 1967 J, M. WASHBURN 3, 4

FEEDING MECHANISM FOR SEWING MACHINE Filed D90. 10, 1965 4 Sheets-Sheet 5 FIG. 6

l9 3' 33 V 22 23 l72O 2| 32 I l 3O 22 i 27 Li FIG. 7

INVENTOR JOHN M. WASHBURN I MAX,

ATTORNEYS.

FEEDING MECHANISM FOR SEWING MACHINE Filed Dec. 10, 1965 4 Sheets-Sheet 4 U 8 m V LO 0' E INVENTOR JOHN M. WASHBURN ATTORNEYS.

United States Patent Ofi ice 3,357,384 Patented Dec. 12, 1967 3,357,384 FEEDING MECHANISM FOR SEWING MACHINE John M. Washburn, Vest Hartford, Conn, assignor to The Merrow Machine Company, Hartford, Conn., a corporation of Connecticut Filed Dec. 10, 1965, Ser. No. 512,840 7 Claims. (Cl. 112-209) This invention relates to feeding mechanisms for sewing machines, and more particularly to an improved feeding mechanism which may be actuated to vary the work feeding movement of the four-motion feed dogs during operation of the sewing machine.

In seaming work pieces on an over-edge or other sewing machine, it is frequently desirable to vary the work feeding movement of the four-motion feed dogs during operation of the machine to thereby vary the length of the in dividual stitches along the seam. For example, it may be desirable to place an increased number of stitches in the seam in areas of high stress such as at the beginning and ends of a seam, with fewer stitches in other portions of the seam. A feed mechanism according to this invention permits the machine operator to vary the feeding movement of the dogs, and thereby the length of the individual stitches, between a predetermined minimum and maximum, as desired, during operation of the machine.

While certain features of the invention are appropriate for more general application, the invention is particularly well adapted for use with an over-edge sewing machine of the well known Merrow type, and the invention is illustrated in the drawings in conjunction with such a machine.

An important feature of the invention resides in replacing the conventional feed carrier link with two link members, or pitmans. One of the pitmans has one end rotatably mounted on an eccentric portion of the lower shaft and the other pitman has one end rotatably mounted on the feed carrier. Both pitmans have their other ends rotatably mounted on a pin carrier by a connecting rod which, in turn, is mounted for pivotal movement about an axis parallel to the axis of the machine lower shaft. Rotation of the lower shaft, acting through the eccentric, imparts a reciprocating movement to the pitman which imparts a rocking movement to the connecting rod to guide said other ends of the pitmans along an arcuate path. The connecting rod is supported on an eccentric pin of a crank which may be selectively rotated to thereby vary the arcuate path and the length of feeding movement imparted to the feed carrier and feed dog.

Other features of the invention will become apparent by reference to the following specification and to the drawings:

FIG. 1 is an end view of a sewing machine of the Merrow type with certain parts omitted or in section to more clearly illustrate the feed and associated mechanism comprising the present invention;

FIG. 2 is a fragmentary end view similar to FIG. I, with certain parts broken away and other parts shown in an alternate position;

FIGS. 3 and 4 are views similar to FIG. 2, with parts shown in alternate positions;

FIG. 5 is a fragmentary horizontal sectional view taken substantially along line 55 of FIG. 3;

FIG. 6 is a fragmentary vertical sectional view taken substantially along line 6-6 of FIG. 1;

FIG. 7 is a series of plan views illustrating the needle plate and feed dogs, with the feed dogs being shown in alternate positions in each View;

FIG. 8 is an end view similar to FIG. 1 illustrating an alternate embodiment of the invention; and

FIG. 9 is a fragmentary sectional view taken substantially along line 9-9 of FIG. 8.

Referring now to the drawings in detail, the invention is shown as applied to a sewing machine which includes a base 1, a mechanism housing 2, and a lower drive shaft 3 supported for rotation by housing 2. The machine also includes a front feed dog 4 and a rear feed dog 5 rigidly supported on feed carrier 6. The feed, carrier 6 is provided with an elongated, open ended slot 7 at its rearward end which receives a rectangular pivot block 8 which, in turn, is pivotally supported on frame 2 by suitable means such as screw 9. The rectangular block 8 cooperates with slot 7 to support the rear end of feed carrier 6 for both horizontal sliding and pivotal movement.

A second open-ended slot 10 is formed on the forward end of the carrier 6 which receives and is supported by a second rectangular block, not shown, rotatably supported on an eccentric portion of shaft 3. Rotation of shaft 3, acting through the eccentric portion, causes vertical oscillating movement of the forward end of feed carrier 6 and of the feed dogs 4 and 5. This arrangement for supporting the feed carrier 6 is substantially as illustrated in United States Patent No. 2,827,869, reference to which may be had for further details of this feature, if desired.

Simultaneously with the oscillatory vertical movement feed carrier 6 is caused to oscillate in a horizontal direction by a linkage mechanism, more fully described hereinbelow, so that the combination of the horizontal and ver tical oscillatory movement of the feed bar moves the feed dogs in a substantially elliptical orbital path to thereby feed work material past the stitch-forming mechanism of the sewing machine. This orbital path carries the feed dogs upwardly to project through slots 13 in needle plate 11 to a position at the forward portion of the machine illustrated in FIG. 1, then rearwardly along a slightly curved path beneath pressure foot 12 to a position substantially as shown in FIG. 2. From the FIG. 2 position, the feed dogs are moved downwardly beneath the upper surface of needleplate 11, and then forward and upward to the position illustrated in FIG. 1, with the cycle being repeated upon each revolution of shaft 3.

The arrangement for driving the feed carrier 6 in its horizontal, or feeding movement, comprises a first pitman 15 having one end rotatably supported on an eccentric bearing 16 carried on shaft 3 and its other end rotatably supported on a connecting pin 17 carried by a connecting rod 18. A second pitman 19 has one end rotatably supported on pin 17 and its other end rotatably mounted, as by bolt 20, to a downwardly depending tab 21 on feed carrier 6. A crank shaft 22 is supported by housing 2 for rotation in bearings 23, 24 about an axis parallel to the longitudinal axis of shaft 3. Crank 22 includes a crank pin 25 supported by crank webs 26, 27, and connecting rod 18 is journaled, as by hearing 28, for rotation about the longitudinal axis of pin 25.

Referring to FIGS. 1-4, it is seen that rotation of shaft 3, acting through eccentric 16, causes reciprocating movement of pitman 15 which, in turn, acts through pin 17 to cause connecting rod 18 to be pivoted about the longitudinal axis of crank pin 25. Pivotal movement of connecting rod 18, acting through pin 17, imparts reciprocal axial movement to pitman 19, which, in turn, imparts horizontal oscillatory movement to feed bar 6 through bolt 20. It is also seen that the rotational position of crank 22 may be varied to shift the position of crank pin 25 and thereby shift the axis of rotation of crank 18. By shifting the axis of rotation of crank 18, the arcuate path followed by pin 17, upon reciprocation of pitman 15, may be varied to vary the horizontal component of movement imparted to crank 19.

The mechanism for rotating crank 22 includes a sleeve 30 rotatably fixed, as by screws 31, 32 on the end of crank 22 for rotation therewith. Sleeve 30 has a gear segment 33 integrally formed thereon which meshes with a similar gear segment 34 formed on the end of an elongated lever member 35 which is pivotally supported on housing 2 as by screw 36. Lever 35 projects forwardly to a position spaced in front of the sewing machine and terminates in a laterally extending paddle-like portion 37 spaced in front of and below the needle plate in position to be actuated by the hand of the sewing machine operator.

Sleeve 30 includes a downwardly extending tab portion 38 in position to engage adjustable threaded stops 39, 46, mounted in threaded apertures in frame 2 in position to limit rotation of sleeve 30 and of crank 22. As best illustrated in FIGS. 1 and 5, crank 22 is resiliently urged for rotation in a direction to position connecting rod 18 to provide maximum travel for feed carrier 6. This is accomplished by a piston 41 slidably mounted within a bore in frame 2, and resiliently urged by a spring 42 into engagement with tab 38 of sleeve 30, thereby urging tab 38 into engagement with stop 39. A threaded adjusting knob 43 mounted within a threaded ounter-bore 44 of frame 2 bears against the end of spring 42 to provide a means for adjusting the spring load applied by piston 41.

To move crank 22 from the position shown in FIGS. 1 and 2 in which the connecting rod is positioned to impart maximum travel to the feed dogs to the position shown in FIGS. 3 and 4 in which the connecting rod is positioned to impart minimum travel to the feed dogs, it is only necessary for the machine operator to depress tab portion 37 of lever 35 to thereby rotate gear segment 33 of sleeve 30. Rotation of sleeve 30 moves piston 41 against the compressive force of spring 42 until tab 38 engages stop 40. Since spring 42 acting through tab 38, is continuously urging sleeve 30 toward the maximum feed position it is necessary to hold lever 35 in the depressed position illustrated in FIGS. 3 and 4 against this spring force for so long as it is desired to decrease the feed movement of the machine. To restore th mechanism to the maximum feed position, tab 37 is released and spring 42, acting through piston 41 and tab 38 of sleeve 30, rot tates crank 22 in a clockwise direction until tab 38 engages stop 39. 1

By rotating crank 22 to vary the position of crank pin 25, the arcuate path traversed by pin 17, and the ends of pitmans 15 and 19 supported thereon, is altered to vary the vertical component of movement of the pin. By varying the vertical component of movement, the horizontal component is simultaneously altered so that the horizontal movement imparted to the feed carrier depends upon the position of crank pin 25.

The effect which rotation of crank 22 has upon the movement of feed dogs 4, 5 is illustrated schematically in FIG. 7 wherein the top view illustrates the position of the feed dogs 4, 5 with respect to needle plate 11, when the respective parts are in position illustrated in FIG. 1 with lever 35 positioned for maximum feed. The view second from the top in FIG. 7 illustrates the position of the feed dogs with respect to the needle plate with lever 35in the maximum feed position as illustrated in FIG. 2 but with lower shaft 3 rotated 180 degrees from the FIG. 1 position. Thus, the two uppermost views of FIG. 7 illustrate the extreme position of th feed dogs when the lever 35 is in the maximum feed position. Similarly, the two lowermost views of FIG. 7 illustrate the extreme positions of the feed dogs with respect to the needle plate when the respective parts are in the minimum feed position illustrated in FIGS. 3 and 4. Thus, it is seen that the length of feed, and consequently the length of the individual stitch formed by the machine, may be varied from the maximum illustrated in FIG. 7 tothe minimum as illustrated in FIG. 7 by the simple expedient of depressing or releasing the tab 37 on lever 35 positioned immediately in front of the stitch forming mechanism of the machine at the operators station.

It is believed apparent that the operator may vary the length of feed, and the length of lever 35 may bedepressed any desired extent less than the extreme pos1 tion determined by adjustable stop 40 to provide any feed and stitch length desired between the maximum and minimum illustrated in FIG. 7. Thus, the mechanism is infinitely variable between the maximum and minimum limits established by the respective position of stop members 39 and 40.

In the embodiment illustrated in FIGS. 8 and 9, the rear feed dog 5 is supported by a second feed carrier 50 which is generally similar to but somewhat shorter than feed carrier 6,.and is supported in side-by-side relation therewith. Feed carrier 50 is provided with an elongated, open-ended slot 51 at its rearward end which receives a rectangular pivot block 52 which, in turn, is pivotally supported on feed carrier 6 by suitable means such as a screw 53. The rectangular pivot block 52 cooperates with slot 51 to support the rear end of feed carrier 50 for both horizontal sliding and pivotal movement. The forward end of feed car-rier 50 is formed with an open-ended slot, not shown, corresponding generally to the slot 10 on feed carrier 6, which receives and is supported on the rectangular block on shaft 3 which supports the forward end of feed carrier 6. Thus, rotation of shaft 3, acting through the eccentric portion thereon, causes simultaneous vertical oscillating movement of the forward end of feed carriers. 6 and 5t and of the feed dogs 4 and 5 carried there Simultaneously, with the oscillatory vertical movement, feed carrier 50 is caused to oscillate in a horizontal direction by a pitman 54 having one end rotatably supported on an eccentric bushing 55 supported on shaft 3, and having its other end rotatably connected to feed carrier 50 by suitable means such as mounting bolt 56. Since pitman 54 is connected directly to feed carrier 50, the rear feed dog 5 will be moved through a fixed orbital path upon each revolution of shaft 3. Thus, in this embodiment, the feeding movement of rear feed dog 5 remains constant while the feeding movement of the front feed dog 4 may be varied by the machine operator by actuation of the variable feeding mechanism described above to produce a differential feeding movement between the two feed dogs.

While I have disclosed a preferred embodiment of my invention, I wish it understood that I do not intend to be restricted solely thereto, but that I do intend to cover all embodiments thereof which would be apparent to one skilled in the art and which come within the spirit and scope of my invention.

What is claimed is:

1. In a sewing machine feeding mechanism having a machine base, a drive shaft rotatably mounted on said base, a feed dog, a feed carrier supporting said dog for oscillatory movement in a vertical and horizontal direction to engage and feed work material through the machine, first eccentric means on said shaft for imparting oscillatory movement to said carrier in a vertical direction, second eccentric means on said shaft, and linkage means connecting said second eccentric to said feed carrier to impart oscillatory movement thereto in a horizontal direction, the improvement wherein said linkage means comprises, a connecting rod, crank means mounted on said base about a first horizontal axis and supporting said connecting rod for pivotal movement thereon about a second horizontal axis spaced from said first horizontal axis, first and second pitmans each having one end rotatably connected to said connecting rod for pivotal movement thereon about an axis parallel to and spaced from said second horizontal axis, said first pitman having its other end rotatably connected to said feed carrier, said second pitman having its other end rotatably mounted on said second eccentric for oscillatory movement thereon upon rotation of said shaft to impart oscillatory pivotal movement to said connecting rod about said second horizontal axis to guide said one end of said first and second pitmans along an arcuate path about said second horizontal axis, and means for rotating said crank about said first horizontal axis between a maximum feed position and a minimum feed position to shift said second horizontal axis and said arcuate path to vary the amplitude of horizontal oscillatory movement imparted to said feed carrier and the feed dog carried thereby.

2. The sewing machine feeding mechanism according to claim 1 wherein said one ends of said first and second pitmans are rotatably connected to said connecting rod for rotation thereon about a common axis.

3. The sewing machine feeding mechanism according to claim 2 wherein said means for rotating said crank includes resilient spring means continuously urging said crank for rotation to said maximum feed position, and selectively operable means for rotating said crank towards said minimum feed position against the force of said resilient spring means.

4. The sewing machine feeding mechanism according to claim 3 wherein said selectively operable means includes an elongated lever, means pivotally mounting said lever on said machine base, and means operatively connecting said crank to said lever for rotation thereby upon pivotal movement of said lever.

5. A sewing machine feeding mechanism according to claim 4 wherein said means operatively connecting said crank with said lever includes a gear segment on said lever, and gear means rotatably fixed on said crank and meshing with said gear segment on said lever for rotation thereby upon pivotal movement of said lever.

6. A sewing machine feeding mechanism according to claim 1 further including adjustable means for varying said maximum and minimum feed positions of said crank to control the range and amplitude of horizontal oscillatory movement of said feed carrier.

7. A sewing machine feeding mechanism according to claim 1 further including a second feed dog, a second feed carrier supporting said second dog for oscillatory movement in a vertical and horizontal direction to engage and feed work material through the machine, and eccentric means on said shaft imparting vertical and horizontal oscillatory movement to said second carrier to move said second feed dog in a fixed orbital path and imparting a fixed work-feeding movement thereto.

References Cited UNITED STATES PATENTS 2,228,220 1/1941 Anton 112208 2,965,056 12/1960 Wallenberg ct al. 112208 PATRICK D. LAWSON, Primary Examiner.

RICHARD J. SCANLAN, IR., Examiner. 

1. IN A SEWING MACHINE FEEDING MECHANISM HAVING A MACHINE BASE, A DRIVE SHAFT ROTATABLY MOUNTED ON SAID BASE, A FEED DOG, A FEED CARRIER SUPPORTING SAID DOG FOR OSCILLATORY MOVEMENT IN A VERTICAL AND HORIZONTAL DIRECTION TO ENGAGE AND FEED WORK MATERIAL THROUGH THE MACHINE, FIRST ECCENTRIC MEANS ON SAID SHAFT FOR IMPARTING OSCILLATORY MOVEMENT TO SAID CARRIER IN A VERTICAL DIRECTION TION, SECOND ECCENTRIC MEANS ON SAID SHAFT, AND LINKAGE MEANS CONNECTING SAID SECOND ECCENTRIC TO SAID FEED CARRIER TO IMPART OSCILLATORY MOVEMENT THERETO IN A HORIZONTAL DIRECTION, THE IMPROVEMENT WHEREIN SAID LINKAGE MEANS COMPRISES, A CONNECTING ROD, CRANK MEANS MOUNTED ON SAID BASE ABOUT A FIRST HORIZONTAL AXIS AND SUPPORTING SAID CONNECTING ROD FOR PIVOTAL MOVEMENT THEREON ABOUT A SECOND HORIZONTAL AXIS SPACED FROM SAID FIRST HORIZONTAL AXIS, FIRST AND SECOND PITMANS EACH HAVING ONE END ROTATABLY CONNECTED TO SAID CONNECTING ROD FOR PIVOTAL MOVEMENT THEREON ABOUT AN AXIS PARALLEL TO AND SPACED FROM SAID SECOND HORIZONTAL AXIS, SAID FIRST PITMAN HAVING ITS OTHER END ROTATABLY CONNECTED TO SAID FEED CARRIER, SAID SECOND PITMAN HAVING ITS OTHER END ROTATABLY MOUNTED ON SAID SECOND ECCENTRIC FOR OSCILLATORY MOVEMENT THEREON UPON ROTATION OF SAID SHAFT TO IMPART OSCILLATORY PIVOTAL MOVEMENT TO SAID CONNECTING ROD ABOUT SAID SECOND HORIZONTAL AXIS TO GUIDE SAID ONE END OF SAID FIRST AND SECOND PITMANS ALONG AN ARCUATE PATH ABOUT SAID SECOND HORIZONTAL AXIS, AND MEANS FOR ROTATING SAID CRANK ABOUT SAID FIRST HORIZONTAL AXIS BETWEEN A MAXIMUM FEED POSITION AND A MINIMUM FEED POSITION TO SHIFT SAID SECOND HORIZONTAL AXIS AND SAID ARCUATE PATH TO VARY THE AMPLITUDE OF HORIZONTAL OSCILLATORY MOVEMENT IMPARTED TO SAID FEED CARRIER AND THE FEED DOG CARRIED THEREBY. 